Coating films are provided on surfaces of rubber elastic bodies such as rubber-coated metal gaskets, bearing seals, oil seals, and O-rings for preventing sticking, preventing blocking, improving wear resistance, and other purposes. However, in spite of formation of these coating films, when exposed to engine vibration under high contact pressure and high temperature conditions of engine gaskets, the rubber coat on the gasket surface may become worn to cause gas leakage. Moreover, the rubber coat layer at a sliding portion of the rubber elastic body, such as a bearing seal or an oil seal, becomes worn due to repeated friction, which may cause oil leakage.
Then, in order to improve the wear resistance, various coating agents have been developed (for example, Patent Literatures 1 to 4).